1/*
  2 * arch/x86/kernel/nmi-selftest.c
  3 *
  4 * Testsuite for NMI: IPIs
  5 *
  6 * Started by Don Zickus:
  7 * (using lib/locking-selftest.c as a guide)
  8 *
  9 *   Copyright (C) 2011 Red Hat, Inc., Don Zickus <dzickus@redhat.com>
 10 */
 11
 12#include <linux/smp.h>
 13#include <linux/cpumask.h>
 14#include <linux/delay.h>
 15#include <linux/init.h>
 16#include <linux/percpu.h>
 17
 18#include <asm/apic.h>
 19#include <asm/nmi.h>
 20
 21#define SUCCESS		0
 22#define FAILURE		1
 23#define TIMEOUT		2
 24
 25static int __initdata nmi_fail;
 26
 27/* check to see if NMI IPIs work on this machine */
 28static DECLARE_BITMAP(nmi_ipi_mask, NR_CPUS) __initdata;
 29
 30static int __initdata testcase_total;
 31static int __initdata testcase_successes;
 32static int __initdata expected_testcase_failures;
 33static int __initdata unexpected_testcase_failures;
 34static int __initdata unexpected_testcase_unknowns;
 35
 36static int __init nmi_unk_cb(unsigned int val, struct pt_regs *regs)
 37{
 38	unexpected_testcase_unknowns++;
 39	return NMI_HANDLED;
 40}
 41
 42static void __init init_nmi_testsuite(void)
 43{
 44	/* trap all the unknown NMIs we may generate */
 45	register_nmi_handler(NMI_UNKNOWN, nmi_unk_cb, 0, "nmi_selftest_unk",
 46			__initdata);
 47}
 48
 49static void __init cleanup_nmi_testsuite(void)
 50{
 51	unregister_nmi_handler(NMI_UNKNOWN, "nmi_selftest_unk");
 52}
 53
 54static int __init test_nmi_ipi_callback(unsigned int val, struct pt_regs *regs)
 55{
 56        int cpu = raw_smp_processor_id();
 57
 58        if (cpumask_test_and_clear_cpu(cpu, to_cpumask(nmi_ipi_mask)))
 59                return NMI_HANDLED;
 60
 61        return NMI_DONE;
 62}
 63
 64static void __init test_nmi_ipi(struct cpumask *mask)
 65{
 66	unsigned long timeout;
 67
 68	if (register_nmi_handler(NMI_LOCAL, test_nmi_ipi_callback,
 69				 NMI_FLAG_FIRST, "nmi_selftest", __initdata)) {
 70		nmi_fail = FAILURE;
 71		return;
 72	}
 73
 74	/* sync above data before sending NMI */
 75	wmb();
 76
 77	apic->send_IPI_mask(mask, NMI_VECTOR);
 78
 79	/* Don't wait longer than a second */
 80	timeout = USEC_PER_SEC;
 81	while (!cpumask_empty(mask) && timeout--)
 82	        udelay(1);
 83
 84	/* What happens if we timeout, do we still unregister?? */
 85	unregister_nmi_handler(NMI_LOCAL, "nmi_selftest");
 86
 87	if (!timeout)
 88		nmi_fail = TIMEOUT;
 89	return;
 90}
 91
 92static void __init remote_ipi(void)
 93{
 94	cpumask_copy(to_cpumask(nmi_ipi_mask), cpu_online_mask);
 95	cpumask_clear_cpu(smp_processor_id(), to_cpumask(nmi_ipi_mask));
 96	if (!cpumask_empty(to_cpumask(nmi_ipi_mask)))
 97		test_nmi_ipi(to_cpumask(nmi_ipi_mask));
 98}
 99
100static void __init local_ipi(void)
101{
102	cpumask_clear(to_cpumask(nmi_ipi_mask));
103	cpumask_set_cpu(smp_processor_id(), to_cpumask(nmi_ipi_mask));
104	test_nmi_ipi(to_cpumask(nmi_ipi_mask));
105}
106
107static void __init reset_nmi(void)
108{
109	nmi_fail = 0;
110}
111
112static void __init dotest(void (*testcase_fn)(void), int expected)
113{
114	testcase_fn();
115	/*
116	 * Filter out expected failures:
117	 */
118	if (nmi_fail != expected) {
119		unexpected_testcase_failures++;
120
121		if (nmi_fail == FAILURE)
122			printk(KERN_CONT "FAILED |");
123		else if (nmi_fail == TIMEOUT)
124			printk(KERN_CONT "TIMEOUT|");
125		else
126			printk(KERN_CONT "ERROR  |");
127		dump_stack();
128	} else {
129		testcase_successes++;
130		printk(KERN_CONT "  ok  |");
131	}
132	testcase_total++;
133
134	reset_nmi();
135}
136
137static inline void __init print_testname(const char *testname)
138{
139	printk("%12s:", testname);
140}
141
142void __init nmi_selftest(void)
143{
144	init_nmi_testsuite();
145
146        /*
147	 * Run the testsuite:
148	 */
149	printk("----------------\n");
150	printk("| NMI testsuite:\n");
151	printk("--------------------\n");
152
153	print_testname("remote IPI");
154	dotest(remote_ipi, SUCCESS);
155	printk(KERN_CONT "\n");
156	print_testname("local IPI");
157	dotest(local_ipi, SUCCESS);
158	printk(KERN_CONT "\n");
159
160	cleanup_nmi_testsuite();
161
162	if (unexpected_testcase_failures) {
163		printk("--------------------\n");
164		printk("BUG: %3d unexpected failures (out of %3d) - debugging disabled! |\n",
165			unexpected_testcase_failures, testcase_total);
166		printk("-----------------------------------------------------------------\n");
167	} else if (expected_testcase_failures && testcase_successes) {
168		printk("--------------------\n");
169		printk("%3d out of %3d testcases failed, as expected. |\n",
170			expected_testcase_failures, testcase_total);
171		printk("----------------------------------------------------\n");
172	} else if (expected_testcase_failures && !testcase_successes) {
173		printk("--------------------\n");
174		printk("All %3d testcases failed, as expected. |\n",
175			expected_testcase_failures);
176		printk("----------------------------------------\n");
177	} else {
178		printk("--------------------\n");
179		printk("Good, all %3d testcases passed! |\n",
180			testcase_successes);
181		printk("---------------------------------\n");
182	}
183}